Structured Data Capture
4.0.0 - International flag

Structured Data Capture, published by HL7 International / FHIR Infrastructure. This guide is not an authorized publication; it is the continuous build for version 4.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/sdc/ and changes regularly. See the Directory of published versions

Extension: Extract Definition - Extract value

Official URL: http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-definitionExtractValue Version: 4.0.0
Standards status: Draft Draft as of 2025-10-22 Maturity Level: 0 Computable Name: DefinitionExtractValueExtension
Other Identifiers: OID:2.16.840.1.113883.4.642.40.17.42.82

Provide either a fixed value, or an expression to evaluate, to be used as the value for the extracted resource's property based on the definition value.

Context of Use

This extension will only be processed while extracting a resource based on a parent item (or root) using either the definitionExtract or itemExtractionContext (legacy) extension. It is NOT valid to specify an extractDefinitionValue prior to (and outside the hierarchy) where the corresponding extractDefinition is found.

It is used to define the value of a property on the resource being extracted, without requiring an item/answer in the questionnaire response (typically for fixed, or derived/calculated values).

The property is based on the value in the definition property, where the prefix (before the #) must exactly match the profile's canonical URL from the extraction context in a parent item/root.

Additional details on the use of this extension can be found on the Data Extraction page.

Usage info

Usages:

You can also check for usages in the FHIR IG Statistics

Formal Views of Extension Content

Description Differentials, Snapshots, and other representations.

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension C 0..* Extension Fixed or calculated value to extract
Constraints: dev-1
... extension 1..* Extension Extension
... Slices for extension Content/Rules for all slices
.... extension:definition 1..1 Extension ElementDefintion to extract value into
..... extension 0..0
..... url 1..1 uri "definition"
..... value[x] 1..1 uri Profile canonical URL and element id
.... extension:expression 0..1 Extension An expression to evaluate
..... extension 0..0
..... url 1..1 uri "expression"
..... value[x] 1..1 Expression Expression value
.... extension:fixed-value 0..1 Extension A fixed value to extract
..... extension 0..0
..... url 1..1 uri "fixed-value"
..... value[x] 1..1 base64Binary, boolean, canonical(), code, date, dateTime, decimal, id, instant, integer, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, Reference(), SampledData, Signature, Timing, ContactDetail, Contributor, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Dosage, Meta Fixed value
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-definitionExtractValue"

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
dev-1 error Extension Either `expression` or a `fixed-value` must be provided. extension('expression').value.exists() xor extension('fixed-value').value.exists()
NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension C 0..* Extension Fixed or calculated value to extract
Constraints: dev-1
... id 0..1 string Unique id for inter-element referencing
... Slices for extension 1..* Extension Extension
Slice: Unordered, Open by value:url
.... extension:definition 1..1 Extension ElementDefintion to extract value into
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0
..... url 1..1 uri "definition"
..... value[x] 1..1 uri Profile canonical URL and element id
.... extension:expression 0..1 Extension An expression to evaluate
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0
..... url 1..1 uri "expression"
..... value[x] 1..1 Expression Expression value
.... extension:fixed-value 0..1 Extension A fixed value to extract
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0
..... url 1..1 uri "fixed-value"
..... value[x] 1..1 Fixed value
...... valueBase64Binary base64Binary
...... valueBoolean boolean
...... valueCanonical canonical(Any)
...... valueCode code
...... valueDate date
...... valueDateTime dateTime
...... valueDecimal decimal
...... valueId id
...... valueInstant instant
...... valueInteger integer
...... valueMarkdown markdown
...... valueOid oid
...... valuePositiveInt positiveInt
...... valueString string
...... valueTime time
...... valueUnsignedInt unsignedInt
...... valueUri uri
...... valueUrl url
...... valueUuid uuid
...... valueAddress Address
...... valueAge Age
...... valueAnnotation Annotation
...... valueAttachment Attachment
...... valueCodeableConcept CodeableConcept
...... valueCoding Coding
...... valueContactPoint ContactPoint
...... valueCount Count
...... valueDistance Distance
...... valueDuration Duration
...... valueHumanName HumanName
...... valueIdentifier Identifier
...... valueMoney Money
...... valuePeriod Period
...... valueQuantity Quantity
...... valueRange Range
...... valueRatio Ratio
...... valueReference Reference(Any)
...... valueSampledData SampledData
...... valueSignature Signature
...... valueTiming Timing
...... valueContactDetail ContactDetail
...... valueContributor Contributor
...... valueDataRequirement DataRequirement
...... valueExpression Expression
...... valueParameterDefinition ParameterDefinition
...... valueRelatedArtifact RelatedArtifact
...... valueTriggerDefinition TriggerDefinition
...... valueUsageContext UsageContext
...... valueDosage Dosage
...... valueMeta Meta
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-definitionExtractValue"

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
dev-1 error Extension Either `expression` or a `fixed-value` must be provided. extension('expression').value.exists() xor extension('fixed-value').value.exists()
ele-1 error **ALL** elements All FHIR elements must have a @value or children hasValue() or (children().count() > id.count())
ext-1 error **ALL** extensions Must have either extensions or value[x], not both extension.exists() != value.exists()

Summary

Complex Extension: Provide either a fixed value, or an expression to evaluate, to be used as the value for the extracted resource's property based on the definition value.

  • definition: uri: This is the profile canonical Url, followed by # and the element id, that the value should be extracted into.
  • expression: Expression: An expression to evaluate to extract the value into the specified element definition. If no value is evaluated, then the element is not extracted.
  • fixed-value: base64Binary, boolean, canonical, code, date, dateTime, decimal, id, instant, integer, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, Reference, SampledData, Signature, Timing, ContactDetail, Contributor, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Dosage, Meta: A fixed value to extract into the specified element definition.

Maturity: 0

Differential ViewDifferential View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension C 0..* Extension Fixed or calculated value to extract
Constraints: dev-1
... extension 1..* Extension Extension
... Slices for extension Content/Rules for all slices
.... extension:definition 1..1 Extension ElementDefintion to extract value into
..... extension 0..0
..... url 1..1 uri "definition"
..... value[x] 1..1 uri Profile canonical URL and element id
.... extension:expression 0..1 Extension An expression to evaluate
..... extension 0..0
..... url 1..1 uri "expression"
..... value[x] 1..1 Expression Expression value
.... extension:fixed-value 0..1 Extension A fixed value to extract
..... extension 0..0
..... url 1..1 uri "fixed-value"
..... value[x] 1..1 base64Binary, boolean, canonical(), code, date, dateTime, decimal, id, instant, integer, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, Reference(), SampledData, Signature, Timing, ContactDetail, Contributor, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Dosage, Meta Fixed value
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-definitionExtractValue"

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
dev-1 error Extension Either `expression` or a `fixed-value` must be provided. extension('expression').value.exists() xor extension('fixed-value').value.exists()

Snapshot View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension C 0..* Extension Fixed or calculated value to extract
Constraints: dev-1
... id 0..1 string Unique id for inter-element referencing
... Slices for extension 1..* Extension Extension
Slice: Unordered, Open by value:url
.... extension:definition 1..1 Extension ElementDefintion to extract value into
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0
..... url 1..1 uri "definition"
..... value[x] 1..1 uri Profile canonical URL and element id
.... extension:expression 0..1 Extension An expression to evaluate
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0
..... url 1..1 uri "expression"
..... value[x] 1..1 Expression Expression value
.... extension:fixed-value 0..1 Extension A fixed value to extract
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0
..... url 1..1 uri "fixed-value"
..... value[x] 1..1 Fixed value
...... valueBase64Binary base64Binary
...... valueBoolean boolean
...... valueCanonical canonical(Any)
...... valueCode code
...... valueDate date
...... valueDateTime dateTime
...... valueDecimal decimal
...... valueId id
...... valueInstant instant
...... valueInteger integer
...... valueMarkdown markdown
...... valueOid oid
...... valuePositiveInt positiveInt
...... valueString string
...... valueTime time
...... valueUnsignedInt unsignedInt
...... valueUri uri
...... valueUrl url
...... valueUuid uuid
...... valueAddress Address
...... valueAge Age
...... valueAnnotation Annotation
...... valueAttachment Attachment
...... valueCodeableConcept CodeableConcept
...... valueCoding Coding
...... valueContactPoint ContactPoint
...... valueCount Count
...... valueDistance Distance
...... valueDuration Duration
...... valueHumanName HumanName
...... valueIdentifier Identifier
...... valueMoney Money
...... valuePeriod Period
...... valueQuantity Quantity
...... valueRange Range
...... valueRatio Ratio
...... valueReference Reference(Any)
...... valueSampledData SampledData
...... valueSignature Signature
...... valueTiming Timing
...... valueContactDetail ContactDetail
...... valueContributor Contributor
...... valueDataRequirement DataRequirement
...... valueExpression Expression
...... valueParameterDefinition ParameterDefinition
...... valueRelatedArtifact RelatedArtifact
...... valueTriggerDefinition TriggerDefinition
...... valueUsageContext UsageContext
...... valueDosage Dosage
...... valueMeta Meta
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-definitionExtractValue"

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
dev-1 error Extension Either `expression` or a `fixed-value` must be provided. extension('expression').value.exists() xor extension('fixed-value').value.exists()
ele-1 error **ALL** elements All FHIR elements must have a @value or children hasValue() or (children().count() > id.count())
ext-1 error **ALL** extensions Must have either extensions or value[x], not both extension.exists() != value.exists()

Summary

Complex Extension: Provide either a fixed value, or an expression to evaluate, to be used as the value for the extracted resource's property based on the definition value.

  • definition: uri: This is the profile canonical Url, followed by # and the element id, that the value should be extracted into.
  • expression: Expression: An expression to evaluate to extract the value into the specified element definition. If no value is evaluated, then the element is not extracted.
  • fixed-value: base64Binary, boolean, canonical, code, date, dateTime, decimal, id, instant, integer, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, Reference, SampledData, Signature, Timing, ContactDetail, Contributor, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Dosage, Meta: A fixed value to extract into the specified element definition.

Maturity: 0

 

Other representations of profile: CSV, Excel, Schematron